Idiopathic avascular necrosis of the femoral head
Epidemiology
Age: 4–10 years
Etiology
Pathophysiology
Avascular necrosis of the femoral head due to a mismatch between the rapid growth of the femoral epiphyses and the slower development of adequate blood supply to the area
Clinical features
- Antalgic gait (on weight-bearing leg)
- Pain in the hip or the upper leg, sometimes projecting to the knee
- Insidious onset, pain may fluctuate depending on physical activity
- Often exacerbated by internal rotation
- FABER test (Flexion, ABduction, and External Rotation) might be positive.
- Restricted range of movement
- Contralateral involvement in ∼ 10% of cases
Tip
Legg-Calvé-Perthes disease should be considered in a child with knee pain.